When not to open the hive

Knowing when not to open a hive is as much a skill as knowing how.

• Below about thirteen degrees, skip the full inspection: brood chills faster than the cluster can recover, and you spend the colony's stores rewarming what your visit cooled.
• Rain rules out opening too, since wet bees chill quickly and moisture working its way into the hive invites disease on top of the immediate stress.
• Strong wind adds chilling risk and makes bees noticeably more defensive even on an otherwise workable day.
• During a dearth, minimize open time regardless of temperature, because exposed honey or syrup can trigger a robbing frenzy strong enough to kill a weaker colony in hours.

And after dark, simply do not: foragers are all home, the colony is more defensive, and you cannot see eggs or a queen well enough for the visit to teach you anything worth the disruption.